Conventionally, there is known a receiver that generates an in-phase signal and a quadrature signal by quadrature-demodulating a reception signal, and calculates the phase of the reception signal based on the in-phase signal and the quadrature signal. The calculated phase is used not only to demodulate transmission data but also to control a frequency. More specifically, when a local frequency (that is, the oscillation frequency of a local oscillator) for down conversion is increased/decreased based on the phase, the local frequency can be made to follow a desired frequency (for example, a carrier frequency). According to this receiver, two analog baseband circuit systems configured to process the in-phase signal and the quadrature signal, respectively, are prepared. Hence, the receiver incurs a high design cost and requires a large circuit area as compared to a receiver including one analog baseband circuit system.